Steve W Posted March 17, 2002 Share Posted March 17, 2002 HI, Bit cheeky but I haven't even got my car YET. It WILL be a "K" Jap' TT (auto) in standard spec' except the dealer is fitting a Mongoose St/St cat'-back system to replace the completely FAFFED original. (THEY chose system and I can't really moan - it's free and THEY are giving 3-year warranty . . ? ?). From all the (VERY interesting) forums you have posted it appears that I could/should replace AT LEAST the 2nd cat' with a pipe (St/St would be nice? I love Stainless!!) [ Mr. Wilsons wares ? ! ? ] 1) Does anyone have any experience with the Mongoose. Is it more like the original than HKS/Blitz etc. If so is there any point fiddling with cats' without replacing the whole exhaust AGAIN ? ? 2) If I ONLY remove the 2nd cat' will it give SOME gain (spool-up etc) and also probably NOT require boost control OR 'Fuel Cut Defend'-ING. OR AM I ON COMPLETELY THE WRONG TACK AND FLOUNDERING IN THINGS I KNOW NOTHING ABOUT (it's OK I can handle the truth) Thanks for even READING this..... (Edited by Steve W at 8:01 pm on Mar. 17, 2002) Quote Link to comment Share on other sites More sharing options...
Syed Shah Posted March 17, 2002 Share Posted March 17, 2002 It is like stock in terms of sound, not sure about power against the HKS ones etc. It is quite a rare exhaust on an MKIV. Yep, it being a J-spec means you might over-boost if you remove both cats. One cat should still help in power terms and give better spool. Hope this helps Quote Link to comment Share on other sites More sharing options...
Steve W Posted March 17, 2002 Author Share Posted March 17, 2002 Thanks... Blimey ('scuse), this computer thingy really IS good for something after all..??? Quote Link to comment Share on other sites More sharing options...
Alex Posted March 17, 2002 Share Posted March 17, 2002 No point in my opinion removeing one Cat...get both out. Chris Wilson's pipes are on my j-spec and it DOES NOT over boost. And it now sounds great too. Taking the cats out will also remove alot of heat out of the system which is a very good idea! As its a K reg you don't need the cats in for the MOT. If you are determined to only remove one the make it the first one. The First cat is the best one to remove at any rate as its the most restrictive and closest to the turbo's (heat) If you remove both FIT A PROPER BOOST GAUGE just to make sure all is going to plan! Enjoy your new toy! Quote Link to comment Share on other sites More sharing options...
michel lane Posted March 17, 2002 Share Posted March 17, 2002 i got a mongoose on mine with the cat removel, the nz site tells you alot about various diameters on the cat replacements and about over boosting. I found is has a nice noice to it, and it did make a hell of an improvement. i fitted a Dsbc at the same time so i can not really help you on the over boosting side. overall its a pretty good manufacture and you dont really pay for the name. so i give it a good thumbs up Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted March 17, 2002 Share Posted March 17, 2002 Chris Wilson's pipes are designed to help stop boost creep. Very good quality workmanship too. Get them both out, they are just in the way. (Edited by Phil Wall at 11:01 pm on Mar. 17, 2002) Quote Link to comment Share on other sites More sharing options...
Steve W Posted March 17, 2002 Author Share Posted March 17, 2002 HELL'S BELL'S.... I just go downstairs to get a drink, and by the time I get back... LOADS MORE ADVICE . . ! ! This site appears to be THE best MkIV site. [ and I've spent about 3 weeks 'surfing' (hate that phrase), while waiting for ME MOTA' ] p.s. I work at an MOT/engine recon' firm and I think I'm right in saying EARLY "K"s ('92) DON'T need cat' test LATE "K"s ('93) DO need cat' test BUT, I'll confirm that tomorrow (NO I can't 'get-it-through', It's a pretty legit' test centre. THANKS ALL..... Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted March 17, 2002 Share Posted March 17, 2002 Just to add a word of caution, and to fly in the face of the advice you've already been given... My J-Spec with both cats out, using CW's pipes, boosted to over *1.5* bar quickly and easily. Mine was so bad that I had to have my first cat put back in, damn shame Some people get away with it, some don't. I was one of the unlucky ones. Graham Quote Link to comment Share on other sites More sharing options...
HedgehogSandwich adi Posted March 18, 2002 Share Posted March 18, 2002 The mongoose has a gorgeous sound to it when fitted to my old mk3, not stupidly loud but enough to sound nice, and the sound is fairly unique and different. Described of as a low frequency blow rather than a rasp or rumble. The finish is good, but the pipes can start to show signs of rusting with a few months, but they'll last for years. Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted March 18, 2002 Share Posted March 18, 2002 Oops, quick apology time. I've just realised I posted something stupid. I didn't have both of CW's pipes, only the front one. The rear cat was replaced with an HKS system. That'll be why I was overboosting. Sorry, Graham Quote Link to comment Share on other sites More sharing options...
Steve Cargill Posted March 19, 2002 Share Posted March 19, 2002 Quote: from Graham Rudd on 12:57 pm on Mar. 18, 2002[br]Oops, quick apology time. I've just realised I posted something stupid. I didn't have both of CW's pipes, only the front one. The rear cat was replaced with an HKS system. That'll be why I was overboosting. Sorry, Graham Graham, what were you boosting to with just the front cat. That's what I've got at the moment and am contemplating removing the front one. I get 12lbs on a bad day and on really cold days I can sometimes hit cut at just under 15lbs. Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted March 19, 2002 Share Posted March 19, 2002 Steve, with the front cat in I get stock boost. I use an EVC to raise it. Graham Quote Link to comment Share on other sites More sharing options...
Darren S Posted March 19, 2002 Share Posted March 19, 2002 Quote: from Phil Wall on 10:57 pm on Mar. 17, 2002[br]Chris Wilson's pipes are designed to help stop boost creep. Very good quality workmanship too. Get them both out, they are just in the way. (Edited by Phil Wall at 11:01 pm on Mar. 17, 2002) Phil, what are the MOT consequences of taking out a) the front CAT only, 2) both CATs? Also, from previous discussions on this it would seem that removing the front CAT is the most advisable, but along with this I hear the mention of boost gauges and the like. Woudl anything else need to be done after removing the front CAT or is that it? Cheers (Edited by Darren S at 1:33 pm on Mar. 19, 2002) Quote Link to comment Share on other sites More sharing options...
Alex Posted March 19, 2002 Share Posted March 19, 2002 Removing CATS... + points 1.) You reduce the heat build up in the exhaust manifold - entire engine cooler. 2.) Improved Midrange grunt 3.) Quicker Spool 4.) Raised boost pressure 5.) CAN improve MPG - points 1.) Can (if not done properly) lead to "boost creep" to whether this will happen you need a boost gauge. 2.) Can p*ss off the neighbours due to louder exhaust note! That could of course be a + point. 3.) Inevitable worse MPG cause you can't control your right foot!!! If you have a J-spec car up to MY1995 then you can technically get away with a non cat MOT emmisions test this means you should not need to put them back in. If you car is not J-spec or is newer than 1995 reg then it WILL be tested for cat reduced emissions. But you should only need to put the second one back in as the 2JZ-GTE engine when running well is very good emissions wise anyway. So the no.1 cat in the down pipe can go in the bin. period! Boost creep only "normally" will occur when you have a front and downpipe combo of more than 2.5" in diameter ie a 2.5" downpipe and a 3" front pipe will allow boost creep but a 2.5" down and front pipe will not USUALLY allow you to naturally boost above 1.2-1.3bar. Get a boost gauge as they are great to show off with :biggrin: especially the playback ones! If your then going to run at 1.2 bar you will need to run high octane fuel and you will need to consider cooling the intake charge...intercooler or ERL water injection. Quote Link to comment Share on other sites More sharing options...
Darren S Posted March 20, 2002 Share Posted March 20, 2002 Cheers for the reply Alex, very much appreciated. To explain, I have a UK car which is totally standard and the thought of getting improved mid-range grunt is appealing,. However, I'm not keen to make too many changes at them moment and so removing the front CAT only seems a sensible first step. Bearing this in mind and based upon your comments, I wouldn't expect to suffer from 'boost creep' or 'over boosting', but fitting a boost gauge would still be advisable as a safety factor. I believe these can replace the left hand dashboard air vent, next to the clock, is that right???? What replacements are available for the removed CAT and what sort of price are we looking at??? Now, this is where the problems start as this is my first Turbo'd car and so the 'boost' dicsussion is very knew to me. Is there something already on this site which will explain all this to me????? Cheers Quote Link to comment Share on other sites More sharing options...
Alex Posted March 20, 2002 Share Posted March 20, 2002 Forgot to mention... Boost "creep" is (correct me if I'm wrong) only found on J-spec Supra's. IMO you can and should fully decat your UK spec Supra - the steel turbo's in your car are more than up to the job and you have a fuel system that can cope. Sorry for misleading you but I tend to write about J-spec Supra's as they are more common and, well, I have one! I run at about 1.1bar fully decatted with only ERL and the standard SMIC. Before hand it ran fine at 1.1bar without the De-cat or ERL... My J-spec seems to be a bit odd to say the least but its not over boosting so I'm a happy bunny! But you will have to put that second cat in for the MOT. And also investigate closing off your EGR system (Exhaust Gas Recirculation?)..its for lowering emmissions but its knock effects, I believe, are to heat the intake charge which is bad...and if the J-spec doesn't have it why the hell should you have to put up with the power/heat hit?? Hope that cleared things up... I paid Chris Wilson a bit over £300 for both Decat pipes - the UK ones are different so make sure you specify them when ordering...also consider this the first decat pipe is 1ft long and the other 3ft yet it costs £150 each because of the econimcs involved...These are tough high quality pipes...how much easier will it be to justify to the other half if you pay £300 odd for two than £150 for a pipe a foot long?? Go on you know you want to...ps Chris says, and I quote, "There's no bl**dy point fitting just one!" :biggrin: (Edited by Alex Holdroyd at 5:50 pm on Mar. 20, 2002) Quote Link to comment Share on other sites More sharing options...
Steve W Posted March 20, 2002 Author Share Posted March 20, 2002 Sorry for Re-Butting in but... Is it 'easy-access' to get the cats off (and fit 1/both pipes) i.e. in the road/outside your house, or, is it far easier on an MOT ramp ?? I'd really like to try to fit them myself/at home but NOT if I'll get stuck halfway (likely to break a siezed bolt/stud). I CAN get it done at work (MOT bay) but would like to be able to change them back myself if I felt like it. [ I know, why would I want to change back, but 'what if' ] I also like the FEELING of doing a BIT myself . . . ! ? Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted March 20, 2002 Share Posted March 20, 2002 Not talking from experience, but allegedly the bolts from the first cat to the turbo outlet can be a bit of a PITA. Quote Link to comment Share on other sites More sharing options...
Alex Posted March 20, 2002 Share Posted March 20, 2002 Best to warm the bolts up thought mine did come straight out after driving to my mate's ramp. There are two pieces if metal (a plate and a bar) which are easily removed to help your access. It is though a PITA - worth it when its done...worthwhile getting some spare studs first! Quote Link to comment Share on other sites More sharing options...
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